Injection mold



March 14, 1950 L. MAzzoNl 2,500,258

INJECTION MOLD Filed Feb. 5, 1947 s sheets-sheet 1 I@mananami@@xaaxcalxo March 14, 1950 1 MAzzoNl 2,500,258

INJECTION MOLD Filed Feb. 5, 1947 s sheets-sheet 2 March 14, 1950 AMAzzoNl 2,500,258

INJECTION MOLD Filed Feb.. 5, 1947 s sheets-sheet s atented Mar.14,195() v1 UNITED sTATEs PATENT OFFICE Lucigalglllance Applicationiiebruary E5, 1947 Serial ,No.726,533` In France .J une 24, 1943 sectioni, Public Law ,ceogAugust s, 1946 Patent expires June 24, 1963 Vv"Thepresent invention relates 'to molds `for the production 4"of articles inmolded material andWmore particularly lsmall articles arrangedinf'la-rge numbers in thefmold.

En-knoW-n 4processes of manufacture `of Varticles ofthe kind inquestion, the disadvantage arises that after -opening `the mold i eacharticle remains connected .with the material which is solidified iny thechannels in lthe mold, and which xconneetstogether all the `articlesmadein the course of -a single operation. It lis necessary, therefore,toA detach these articles :one by one :which v-involves 1a supplementary`operation lof careful anishing which is `slow Aand relatively costlylin Athe caseof articles of small 4individual lmonetary value.

'The lpresent invention has for its object .to provide a mold permittingof avoiding thementioned disadvantage, by positioning the outlet of ithe:channel Ifor injecting the molding `material corresponding to-thearticle .to .be produced, at fthe ybottom Aof a l.depression provided`on the latter. By rreason lof .this lparticular .arrangement,` Vszvhen,the :material y:is Abroken at the `right of the zpoint ofattachment ofthe arti-cle pto the material lling ithe channels of 'the mold, thefracture is :produced :at 'the exact `center of the depression. It doesnot alter the general symfv lozenges having .a 4central depression andmolding them directly on '.aconnecting braid orcord.

The Apresent invention, :mor-cover, concerns the applicationbfa mold ofythis kindto the productionof pseudo-fabricsfformed by parallel .threadsor braids connected by pastilles with a central depression surmountingthem in pairs.

The pastilles referred to may take any desired -`form, Vfor examplerthat of thin plates, .and they may vthusisnrmourlt more than twothreads according 'tio circumstances.

The A,present invention rhas additionally for fits obj ec't :to Yprovide -atmold more especially intended for carrying :out the above:deined method, the mold being characterisedmainlyiinthat the seperationor' the mold is ,carried out fin y-Itwo steps, the `:first.corresponding .to lfthe removal of vthe material `filling ithe4injection f'channels while the articles remain :held therein whicheproduces the breakage of `the :connection between the latter and themass, and the second corresponding to. the removal lof the moldedarticles themselves.

separated and nished.

=It `is moreover to be understood that l'the lpresent invention alsoincludes articles manufac-f tured by the .above method and particularlythose= obtained by means of a mold of the kind -de" scribed.

The annexed drawing, ,given by way of ex-r ample, :will permit .of -abetter understandingv of the present invention, the features which lit'presents, ,and the advantages :which itis `capable of .alording Fig. lis a fragmentary diagrammatic view ofi a chaplet .according .to thepresent invention.

Fig. 2 is a view to an `enlarged scale showing the carrying out themolding operation according to,Figs..3 to 6.

,Fig p9 :is an :end lview of one of the 'parts of. the mold 'in :whichthe plane of the :section of:

Fig. 8 is indicated Yat -VII-VIIL Fig. 10is a section on V:the line .X-Xof ligullv iFig.. 1l is 1a `,diagrammatic section .showing .toa smallscale the position of -the mold during the injection :of the material.

Figs. 12 Vand y13 respectively indicate to asmall scale :and to `aslarge yscale `a pseudo-fabric according to `the present invention.

Fig. 14 shows another type of pseudo-fabric comprising shaped smallplates.

stituted by a lseries of `pastilles or lozenges for beads pmoldedionfacord f2. fEach pastille :is .of

circular fornrand has at its lrenter va depression 3. sign??showsfthedetail ofthe shaneiof aras` tille :with Athe two .depressions`opposite :one .another von opposite 1faces.

The pastilles il .aremolded :in,a.inoldfcomprls-. ing La ,certain:number `of superposed parts s4, .5,1

6,11 as lindicated rinli'ig. 3. The :mold has successive die cavities or:impressions of fthe form ofthe pastilles to be molded and theseimpressions are Lconnected byfa @groove 8 in which may 3 mission of theinjection material. Each channel 9 leads into the corresponding diecavity or impression at the center of the bead or at the bottom of thedepression 3, by a conical part terminating in a connecting opening ofvery small diameter.

When the material is injected and solidified in the closed mold, theparts appear as indicated in Fig. 3, the channels 9 being lled withmaterial which forms what may be called the injection "carrot or runnerI0. The pastilles or beads are all connected with the carrot in onepiece.

In order to detach them, the carrot is rst freed by raising the upperparil I of the mold (Fig. 4). Then the guard 6 is raised while the part5 is held against the part 4. The molding die cavities or impressionsbeing provided between the parts 5 and 4 which are held, the moldedbeads or pastilles cannot rise. On the other hand, the carrot or runneris lifted by the guard part 6 located beneath it. The carrot is thussubjected to a pull which causes a breakage at the point of leastresistance, that is to say at the right of the outlet of each conicalchannel 9 at its restricted orice into the die cavity at the bottom ofthe corresponding depression 3 (Figs. 5 and 7) and it is thus torn awayfrom the molded bead.

It only remains to lift the part 5 to separate the pastilles or beadsmolded on the braid 2, nished and entirely independent of any injectioncarrot (Fig. 6). The break between the pastille and the carrot takesplace at the bottom of the depression 3 where its resultant roughsurfaces cannot affect the wearer.

Another important advantage of the central depression 3 provided on eachface of the pastille I (Fig. 7) is to create at the outlet of theinjection channel 9 a zone of reduced thickness in which the braid 2 isto some extent held, which prevents the latter from being deformedexcessively, under the action of the pressure of the material on itsentry under pressure. The braid remains thus substantially in the middleplane ofthe pastille, which avoids any unsatisfactory result.

The essential elements of the mold according tothe present inventionwill be apparent from the preceding description by reference to Figs. 34

to 7. The mold comprises parts providing for the real molding of thearticles (parts 4 and 5), separate parts providing for the formation ofthe carrot or runner (parts 6 and 1). and means by virtue of which thecarrot is torn from the molded parts still held between the partscorresponding to them. Figs. 8 to l1 show one example of construction ofa machine using such a mold.

The mold die plates and locking parts 4, 5, 6 and 'I (Fig. 8) are placedone on top of the other, the end parts 4 and 1 being extended to formheads held respectively between the two halves of a lower locking plateII and of an upper plate I2'and adapted to be pressed against oneanother by a suitable press. Posts I3 (Fig. 10) connected to the lowerpart 4 provide for the guiding of the various parts. The upper part 'Icarries the injection orice I4 leading to channels I5 (Figs. 8 and 10)by which the molding material. passes to the individual channels abovedescribed.

The mechanism for opening the mold com'- prises a tubular central pushrod I6 Xedly attached to a movable plate II located in a. suitablechamber I8 in the lower plate II, the plate I'I xedly carrying four pushrods I9 (Figs. 8 and 9) xed to the guard plate part 6 forming the headof the individual channels 9.

The push rods I9 pass freely through the lower part 4 of the mold andpass also through the sockets 20 iixedly attached to the die plate parts5 forming the base of the channels 9 and the top of the molding diecavities, the said sockets passing with gentle friction through thelower part 4 in which they slide freely. The push rods are provided withenlarged shoulders 2I which, normally disposed in a recess in thesockets 20, abut against the latter when the push rods I9 have beenraised to a certain extent, themselves thus moving the part 5 itself.

Finally, the tubular central push rod I6 is traversed by a solid pushrod 22 threadedly operating a plate 23 which carries three rods 24(Figs. 8, 9 and 10) which, passing through the parts 4, 5, 6, pushagainst the solidified runner material in channel I5 and form ejectorsfor the "carrot in the part 6 of the mold.

A strong spring 25 urges the entire assembly4 of the push rodsdownwards. On the other hand;

the springs 2u" mounted on the push rods I9 tend to raise the guard part6 with respect to the part '5, pressing against the shoulders of sockets20.;

A convenient means for bringing together andA separating lower lockingplate l and upper plate I2 may consist of a knuckle joint arrangement.

The upper supporting annular plate 49 and the lower block 4I] arecarried on the frame 50 of the molding machine.

30 bears against the lower face of locking plate II.

tral aperture of annular block 30.

The two plates II and I2 are each made in two halves to permit theinsertion and removall elements 3Ia, 32a, 33a, 34a, 31a, 38a. Shaft 36-has two oppositely threaded portions 35, .35a,- which respectivelyengage threaded sleeves 34,. 34a. When shaft 36 is rotated in thedirection ofthe arrow, the two sleeves 34, 34a, are driven away fromeach other, and the two knuckle joints bend and retract, and sincepivots 38, 38a, are xed with reference to the frame, the block 30 ispulled down and pulls down with it plate II. Rod 22 carries at its lowerend a nut 42. A bolt 43 having a head 4I is bolted through plate 39 andheld thereagainst by nuts 44, 45. During the course of the downwardtravel of plate I I, the

nut 42 descends to strike head 4I, which stops further travel of nut 42and flange 22a and pushes rod 22 upwardly against the action of spring25.

when the shaft 3s is rotated in the directionf opposite to the arrow,the sleeves 34, 34a are re-L turned toward each other and extend thearms 3l, 32, Sla, 32a, to the position shown in Fig. 8, and the mold isclosed. Pressure is thus applied to press together plates II and I2.

The material to be molded is held in receptacle 4l and it passes throughchannel 46 to injection` orifice I4. An annular heating element 48 maybe provided surrounding the receptacle.

The lower fixed plate 39; is attached to block 40. An annular thrustblock.`

A downwardly projecting shoulder of the lower part of plate II extendsthrough the centhe epocas@ .1' I'I'heroperationis' as. follows: v Y

against the action of the springs 26, the material isinjected by meansof theinjection device. Fig.

l1 4shows the general arrangement of the partsy descends downwardly awayfrom fixed upper. part 'l by Virtue ofthe action` ofy the knuckle jointarrangement 3I--35. 'The spring 25 is sufficiently strong tohold theplates Z55 andv Il at the bot-L tom of the chamber I3 in spite of theaction of they springs 26. which tend to raiser the guard part 6 withthe push rods I9.

The central solid push rod 22 is now progressively operated, which maybe done manually or by means oi the control shown, and against theaction of the spring 25, which raises the plate 23 (with the rods 24)and permits the plate I1 to rise under the action of the springs 26taking with them the guard part 6 which raises with it carrot which istorn from the molded parts as explained above with reference to Fig. 5.The guard part 6 ceases to rise when the shoulders 2| abut against theshoulders of sockets 20. Then the rods 24 continuing their upwardmovement engage the solidiiied runner in channel I5 and eject the carrotAs the upward movement of the central solid push rod 22 continues as bymanual actuation, the outer tubular push rod I6 is eventually displacedin turn. The plate I1 then resumes its upward movement raising the pushrods I9 which, by the sockets 2Q, raise the upper die plate part 5 whichreleases the molded parts them- V selves and permits their removal. Thebraid or cord can then be advanced by a suitable amount in order to moldon it a new row of beads or pastilles.

As Fig. 9 shows the mold is arranged to mold simultaneously two seriesof beads or pastilles on two separate braids.

As has been explained above, the present invention is applicable notonly to beads or pastilles mounted on a single cord or braid after themanner lof a chaplet, but also to pseudo-fabrics formed of parallelthreads connected in pairs by beads or pastilles mounted on two threadsat a time. Figs. 12 and 13 show such an arrangement. It will beunderstood without further explanation that the method vof manufactureremains identically the same except that the mold comprises a certainnumber of adjacent rows of impressions or die cavities arranged inquincunx with grooves for the location of the threads arranged to vcutalternately one impression of one row and one of another. Here, thecentral deu pressions 3 can no longer serve to centre the thread onwhich the pastille or bead in question is mounted since each pastille` lis mounted on two lateral threads 2' (Fig. 13). Their purpose is thus tohide the small break separating the pastille from the carrot which iscreated on opening the mold. Often enough this can be dispensed withWithout disadvantage.

`Instead of constructing a pseudo-fabric: by'

means of circular pastilles or heads` surmounting two threads as inFigs'. 12l andv 13,y plates of any other desired form may be provided`mountedon` any number of threads. Fig. 14 shows an example of such aconstruction. Plates Ia, Ib and lc ot difierentforms for the purpose otmaking a dit ferent; design, extend over and engage five to seventhreads. It will be seen. thatthere canv thus be produced a whole seriesof different. de.- signs. It is, in general, easy to arrange the: pointof connection of each plate tothe carrot at a point of the design wherethe break is invisible;l at an angle, projection, etc. or in adepressionpro'- vided for the purpose.

It should be understood that the` preceding de.. scription is given onlyby way of example and' doesnot limit the scope of the present inventioninany way. No departure from the invention` would be made by replacingthe detailsI of construction described by other equivalents.` A=l-'though the present. invention isf more especially intended. for themolding of beads or pastilles or" l the like on braids or cords, itcould equally well:

be applied with advantage to the molding of' arti .cles separate anddistinct from any connecting cord or braid such as counters, buttons,etc. In spite of the advantage which a mold of the kind described offersor of any other equivalent, the method described can likewise beemployed with any known type of mold, pulling the articles from thecarrots after the mold has been opened either by hand or by suitablemechanical means.

It will be apparent to those skilled in the art that my invention issusceptible of modifications to adapt the same to particularapplications, and all such modifications which are within the scope ofthe appended claims I consider to be comprehended within the spirit ofmy invention.

I claim:

1. In a molding machine for molding small objects such as beads, a lowerdie plate, an upper die plate, a guard plate positioned above said upperdie plate, an upper locking plate positioned above said guard plate, alower locking plate positioned below said lower die plate, and iixedlyattached thereto, said upper die plate and said guard plate beingprovided with registering downwardly tapered conical tubes terminatingby a restricted orice in the registering die cavities of said dieplates, said upper locking plate being provided with a distributingchannel connected to the upper enlarged base ends of said tubes, saidlower locking plate being provided with a central recess, a master platemounted within said recess, a hollow shaft, said lower locking platebeing provided with an aperture wherein said shaft is slidably received,said master plate being ixedly attached to said shaft, said lower dieplate and said upper die plate being provided with bores extending fromsaid recess in said lower locking plate to said guard plate, rod memberspassing through said bores and being iixedly` attached to said masterplate and to said guard plate, rst resilient means urging apart saidupper die plate and said guard plate, second resilient means urg ingsaid shaft downwardly and outwardly from said lower locking plate, saidsecond resilient means being in normal position substantially morepowerful than said rst resilient means, said rod members and said upperdie plate comprising mutually engageable limiting means adapted to limitthe displacement of said rod members through said upper die member aftera. determined travel of said rod members and thereafter causing said rodmembers to displace said upper die plate relative to said lower dieplate, a spindle displaceably mounted within said tubular shaft andcarrying at its outer end enlarged terminal means abutting the outer endof said shaft, and being threaded at its inner end, an auxiliary platepositioned above and adjacent said master plate and being provided witha threaded aperture for receiving the threaded end of said spindle, aplurality of auxiliary rods carried by said auxiliary plate andextending through apertures in said die plates and said guard plate intoengagement with material in said distributing channels, wherebyprogressive displacement of said spindle automatically rst permits saidrst resilient means to separate said guard plate from said upper dieplate and thereby tear solidified molding material Within said tubesfrom conneotion with molded objects in the die cavities at saidrestricted orifice thereof, and second to liit the runners in saiddistributing channels carrying the solidified material in said tubesaway therefrom, and third to lift said upper die plate from said lowerdie plate.

REFERENCES CITED l The following references are of' record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 2,302,342 Nast Nov. 17, 19422,341,404 Winterhalter Feb. 8, 1944 2,415,961 Nast Feb. 18, 1947 OTHERREFERENCES Mold designed to trim sprues, Modern Plastics, March 1942.Copy in Div. 15.

Ser. No. 285,944, Swarovski (A. P. C.) published April 27, 1943.

